Small things, big changes

Human beings have existed for only a short time in the Earth's long history, and civilisation is only about 12,000 years old. Yet in that short time we have changed the planet hugely: we have spread across it, cut down forests and filled the air with smoke.

By burning fossil fuels, we have put a blanket of carbon dioxide around the world, which is slowly warming the planet. Antarctica is the best place to study this, because its ice holds a record of the past, and its ecosystem is simple and sensitive to change.

The author went with Students on Ice, a programme founded by Geoff Green that takes high school students to Antarctica. The idea is that young people, who will make the decisions of the future, should see the problem with their own eyes. When they see glaciers retreating and ice shelves collapsing, they understand that global warming is real, and they are inspired to act.

In the Southern Ocean, tiny single-celled plants called phytoplankton use the sun's energy to make food, and they feed the whole food chain of the ocean, and help regulate the planet's carbon. If the ozone layer grows thinner, more ultraviolet light will harm them, and with them every creature that depends on them.

One day the ship stopped, and the passengers walked on the frozen ocean, a thick sheet of ice with deep water below it. Standing there, the author felt that everything is connected. The lesson of the phytoplankton is simple: take care of the small things, and the big things will fall into place.